Almost 5 percent of paid search spending in the US is now in mobile, according to a report released last week from banking and investment firm Macquarie Group, using Efficient Frontier data. That mobile search spend could double to almost 10 percent by the end of this year if growth continues at an aggressive pace.

Using some very rough math that would mean US mobile paid search could be worth approximately $1.1 billion (at least) by the end of 2011. And almost all that money would be Google’s.

Google Market rate Paid search on mobile

Just as Google dominates mobile search share in the US (with roughly 98 percent), the report said that 97 percent of mobile search spend (for Efficient Frontier clients) now goes to Google, while 3.2 percent spend goes to Bing/Yahoo.

Given the massive number of apps now on both the iPhone and Android some people (especially tech bloggers) complain regularly about the “problem of app discovery.” In fact we don’t know if regular users are similarly vexed. But let’s assume they are. On Android in particular “app discovery” has been less than optimal.

Now iPhone “app search engine” Chomp has introduced a version for Android that will help address the problem. Actually Chomp is more like “Yelp for the app store” and it’s been quite successful for iPhone users. The Android version could easily match that success.

Users can either search via the PC site or the Android app itself. In my short time playing with the Chomp Android app I found the experience to be very good.

Chomp

The Chomp Android app allows you to browse or search, although search is emphasized over browsing. Chomp creates an inventory of all your installed apps and then invites you to review them. Beyond its general usability, Chomp’s reviews help differentiate it. Chomp also offers recommendations.